Space Chamber Reaches Cold Target at Unprecedented Efficiency

NASA’s Space Environment Simulation Lab Chamber A, which is used by the agency to to subject components of the James Webb Space Telescope to the rugged conditions it will encounter in space when it is launched in 2018. To achieve the super cold temperatures of outer space inside Chamber A, NASA turned to Jefferson Lab and its cryogenics experts to help devise a new cooling system. Chamber A was originally built in the 1960s to test the Apollo Service and Command module for its trip to and from the moon.

The Office of Nuclear Physics funds a community of scientists to do basic nuclear physics research that seeks to uncover the fundamental nature of matter. As a consequence of this basic research, many ideas and instruments (funded through various sources) have found their way into many different areas in public life as well as in other government programs. This highlight is an example of such a "spinoff".

The Science

The Jefferson Lab cryogenics group re-designed a decades-old cryogenics plant, integrating existing components with a new thermo-siphon design and applying a recently patented process developed at the DOE’s Jefferson Lab known as the Floating Pressure - Ganni Cycle. These, together with other improvements, led to the development of one of the world's most efficient cryogenic refrigeration systems.

The Impact

The breakthrough technology is making it possible for NASA to replicate the super cold temperatures of outer space so that it can test components of the James Webb Space Telescope.

Summary

As the U.S. sweated through its warmest summer on record outside, an enormous testing chamber at NASA Johnson Space Center in Houston reached its coldest temperatures yet on the inside, cooled by one of the world's most efficient cryogenic refrigeration systems. “Chamber A” is mammoth, having a hinged door over 12 meters in diameter, a height of over 36 meters, and a diameter of almost 20 meters. Designed by members of the U.S. Department of Energy’s Jefferson Lab's Cryogenics group in Newport News, VA, the system reached its target temperature of 20 Kelvin, about -424 degrees F, for the first time in May and again during commissioning tests in late August. It reached its target temperature in just over a day and maintains a steady temperature with less than a tenth of a degree in variation over a load temperature range of 16 to 330 Kelvin, all with no loss of helium and using half the liquid nitrogen than comparable systems. But what is even more remarkable is its ability to maintain design efficiency down to a third of its maximum load. "The range of load temperature and capacity while maintaining peak efficiency and temperature stability is unprecedented," said Venkatarao (Rao) Ganni, deputy Cryogenics Department head at Jefferson Lab, and a key member of the system design team. The successful cool down is great news for NASA, which will use the Space Environment Simulation Lab Chamber A to subject components of the James Webb Space Telescope to the rugged conditions it will encounter in space when it is launched in 2018. The Jefferson Lab cryogenics group has pioneered new technologies that led to improvements in the efficiencies of the laboratories' cryogenics systems, applying the concepts of its patented Floating Pressure (known as the Ganni Cycle) and other improvements to reduce the cost and improve the efficiency and stability of cryogenics operations.